"Lol. We look forward to watching Mitt and Newt suck-up to The Donald with a big bowl of popcorn," he said in an email to Business Insider.

Huntsman declined to meet with Trump at his New York offices, his campaign said, though Trump said last month that it was he who declined to meet Huntsman.

Deciding to sit-out the debate may help Huntsman with his message that he is the only adult in the GOP field. Another reason is more practical — Huntsman is wagering everything on New Hampshire, and leaving the state for even a day to debate in Iowa detracts from time he can spend wooing Granite State voters.